title: Cadmium and lead in grey wolf liver samples: optimisation of a microwave-assisted digestion method.
abstract: A microwave-assisted digestion method for the determination of cadmium (Cd) and lead (Pb) by inductively coupled plasma mass spectrometry (ICP-MS) was optimised on certified reference material (CRM) (bovine liver, BCR-185R) and wolf liver samples. Different factors influencing digestion efficiency (temperature, time, composition of the digestion mixture, sample mass) were tested. Validation included linearity (up to 200 μg L(-1) for Cd and Pb), detection (0.003 μg L(-1) for Cd and 0.035 μg L(-1) for Pb), and quantification (0.008 μg L(-1) for Cd and 0.081 μg L(-1) for Pb) limits. Good agreement between measured and certified values was achieved in all conditions, with recoveries ranging from 94 % to 111 % for Cd and from 95 % to 105 % for Pb. The precision of the method, expressed as relative standard deviation, was up to 3 % for Cd and 8 % for Pb. The best digestion parameters (260 °C, 30 min, 1 mL HNO3+4 mL H2O, 0.1 g of CRM) based on accuracy and precision were applied on two wolf liver samples to evaluate the need for the predigestion step (freeze-drying) and appropriate mass of the sample. Freeze-drying improved precision and minimising the tissue mass to 0.1 g reduced the matrix effect. Using these optimised digestion conditions, we determined Cd and Pb in 40 wolf livers collected in Croatia, and their medians (0.055 μg g(-1) and 0.107 μg g(-1), respectively) were in the range of previously reported data for the grey wolf.
authors.forename: Maja
authors.initials: M
authors.lastname: Vihnanek Lazarus
authors.forename: Ankica
authors.initials: A
authors.lastname: Sekovanić
authors.forename: Zorana
authors.initials: Z
authors.lastname: Kljaković-Gašpić
authors.forename: Tatjana
authors.initials: T
authors.lastname: Orct
authors.forename: Jasna
authors.initials: J
authors.lastname: Jurasović
authors.forename: Josip
authors.initials: J
authors.lastname: Kusak
authors.forename: Slaven
authors.initials: S
authors.lastname: Reljić
authors.forename: Duro
authors.initials: D
authors.lastname: Huber
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002104:Cadmium / Q000032:analysis*; D002138:Calibration; D002417:Cattle; D017523:Croatia; D004784:Environmental Monitoring / Q000379:methods*; D005612:Freeze Drying; D006861:Hydrogen Peroxide / Q000737:chemistry; D007854:Lead / Q000032:analysis*; D008099:Liver / Q000737:chemistry* / Q000528:radiation effects; D008872:Microwaves; D017942:Nitric Acid / Q000737:chemistry; D019596:Wolves
chemical_list: D002104:Cadmium; D007854:Lead; D017942:Nitric Acid; D006861:Hydrogen Peroxide